Mobile robots and other wheeled devices operated indoors often collect debris which winds around the axle between the rotating wheel and the stationary housing. The debris commonly includes hair and thread, but may also include other materials that can become entangled such as carpet fibers, lint, string, dental floss, for example, and combinations thereof. The rotation of the wheel produces a winding motion that wraps the debris caught by the wheel tread in between the rotating wheel and the structure to which the wheel is connected. As this debris accumulates around the axle, it generates friction that resists the rotation of the wheel and creates a drag on the motor driving the wheel. The accumulation of even more debris can prevent the wheel from turning all together. There is therefore a need for a wheel design that inhibits debris from bundling around the axle where it can prevent the wheel from turning.